MicroRNA319a regulates plant resistance to Sclerotinia stem rot

Author(s):  
Weiguo Dong ◽  
Wenqing Ren ◽  
Xuan Wang ◽  
He Yuke

Abstract MicroRNA319a (miR319a) controls cell division arrest in plant leaves by inhibiting the expression of TCP (TEOSINTE BRANCHED 1/CYCLOIDEA/PCF) family genes. However, it is unclear whether miR319a influences infections by necrotrophic pathogens and host susceptibility. In this study, we revealed that miR319a affected plant resistance to stem rot disease of Sclerotinia sclerotiorum. In the plants of Brassica rapa infected with S. sclerotiorum, miR319a levels increased while expression levels of several BraTCP genes significantly decreased compared with those of the uninfected plants. The overexpression of BraMIR319a in B. rapa increased the susceptibility of the plants to S. sclerotiorum and aggravated stem rot disease, whereas the overexpression of BraTCP4-1 promoted the plant resistance. Our RNA-sequencing data revealed a potential relationship between miR319a and pathogen-related WRKY genes. Chromatin immunoprecipitation (ChIP) assay, electrophoretic mobility shift assay (EMSA) and reporter transaction assay showed that BraTCP4-1 was bound to the promoters of WRKY75, WRKY70, and WRKY33 genes and directly activated these pathogen-related genes. Moreover, the expression levels of WRKY75, WRKY70, and WRKY33 in the plants overexpressing BraMIR319a declined significantly whereas those of the plants overexpressing BraTCP4-1 increased significantly. These results suggest that miR319a and its targeted gene BraTCP4 regulate stem rot resistance through pathways of WRKY genes.

Author(s):  
R. K. Mishra ◽  
A. K. Parihar ◽  
T. Basvaraj ◽  
Krishna Kumar

Rajmash (Phaseolus vulgaris L.) is one of the important legume crops of North and Central India. This crop is commonly affected by most devastating diseases like powdery mildew and stem rot. Therefore, identification of new resistance source is urgently needed to achieve potential yield. In present investigation fifty-two genotypes of rajmash comprising landraces, cultivars and exotic genotypes were screened against powdery mildew and stem rot diseases under natural field conditions during rabi 2014-15 and 2015-16. The results revealed that, out of 52 genotypes screened against powdery mildew disease, four genotypes/cultivars were free from powdery mildew disease, 16 were found resistant, 12 were moderately resistant, 4 were moderately susceptible, 10 were susceptible and 6 lines were highly susceptible. In case of Sclerotinia stem rot disease, out of 52 genotypes 20 genotypes exhibited resistance, 12 moderately resistance, 7 found susceptible and 5 genotypes were highly susceptible. Furthermore, only four genotypes viz., EC150250, BLF101, EC 565673A and GPR 203 demonstrated resistance reaction against both powdery mildew and stem rot disease. Thus, these genotypes could be used in breeding programme as donor for development of disease resistant varieties against powdery mildew and stem rot disease in future.


2009 ◽  
Vol 157 (1) ◽  
pp. 63-69 ◽  
Author(s):  
Ai-Rong Wang ◽  
Chun-Hua Zhang ◽  
Li-Li Zhang ◽  
Wen-Wei Lin ◽  
De-Shu Lin ◽  
...  

2020 ◽  
Vol 112 (6) ◽  
pp. 5143-5157
Author(s):  
Jianglin Zhang ◽  
Jing Li ◽  
Guotao Geng ◽  
Wenshi Hu ◽  
Tao Ren ◽  
...  

Plant Disease ◽  
1997 ◽  
Vol 81 (3) ◽  
pp. 311-311 ◽  
Author(s):  
K. F. Chang ◽  
R. J. Howard ◽  
R. G. Gaudiel ◽  
S. F. Hwang

Stevia (Stevia rebaudiana Bertoni; Asteraceae), an annual plant originating from Paraguay, contains glucosides of a diterpenoid (2), which is used as a low-caloric sweetener in some South American and southeast Asian countries. The main active ingredient, stevioside, is 100 to 300 times as sweet as sucrose. Stevia has been experimentally grown under field conditions in central and western Canada and has the potential to become a commercially viable alternative crop. In August 1996, a previously undescribed stem rot disease was observed on stevia plants at the Crop Diversification Centre South, Brooks, Alberta. The disease was found in research plots where 4-month-old plants were growing in loam soil. Diseased stems showed dark brown lesions above and at soil level when plant height reached approximately 30 cm. Under dry conditions, mild stem lesions caused plant stunting with lower leaves turning black and curling downward. Wilted leaf symptoms gradually spread upward in affected plants. Partial wilting symptoms appeared when girdling was restricted to branches. The entire plant collapsed when girdling of the crown and roots occurred. Superficial white mycelium developed over the basal part of affected stems under moist conditions, especially after rainy periods. Black, round to oblong sclerotia, 3.5 to 10.1 mm in size, formed externally on the crown areas after plant death. Sclerotinia sclerotiorum (Lib.) de Bary (1) was consistently isolated from the diseased plants. To confirm pathogenicity, 4-week-old stevia seedlings were obtained from shoot cuttings and grown in 12-cm pots of soilless mix. Sclerotia produced on potato dextrose agar were inserted into the mix 0.5 cm deep and 0.5 cm from the stems of test plants. Plants were placed in a growth chamber at 22°C with a 12-h photoperiod and 95% relative humidity. Two weeks after soil infestation, plants wilted and S. sclerotiorum was reisolated from the diseased crown tissues. This is the first report on stevia of sclerotinia stem rot, a disease that could significantly reduce foliar growth and stevioside production in field plantings. References: (1) L. H. Purdy. Phytopathology 69:875, 1979. (2) T. Robinson. 1991. The Organic Constituents of Higher Plants: Their Chemistry and Interrelationships. 6th ed. Cordus Press, North Amherst, MA.


2018 ◽  
Vol 3 (02) ◽  
pp. 171-175
Author(s):  
Devesh Pathak ◽  
R. U. Khan

Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum (Lib.) de Bary is a major disease of rapeseed-mustard and it is considered next to Alternaria blight in causing yield losses as much as 70 per cent in susceptible crop. The pathogen survives in the form of sclerotia on plant debris or in soil for more than 4 years, which makes it very difficult to manage with conventional approaches. Therefore, its management with fungicides and bio-control agents remains an effective approach. The present study was undertaken in-vitro, using four fungicides viz., vitavax, propiconazole, mancozeb and azoxystrobin at three different concentrations i.e. 0.05%, 0.1% and 0.2% and three species of Trichoderma viz., T. harzianum, T. viride, T. koningii,to find out their relative efficacy in inhibiting mycelial growth of the pathogen. It is evident from the observations that all four fungicides and three Trichoderma spp. resulted a significant effect on growth inhibition of S. sclerotiorum. Among all fungicides tested, vitavax and propiconazole were most effective at all three concentrations (0.05, 0.1 and 0.2 %) and inhibited cent percent radial growth of the pathogen, while mancozeb and azoxystrobin were least effective. Among the bio-control agents, T. viride was noted to be most effective antagonist followed by T. koningii resulting 78.50% and 72.21% growth inhibition, respectively. Whereas, T. harzianum showed minimum radial growth inhibition (49.25%) of S. sclerotiorum in this study.


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